Myopia, Long-Sightedness, Presbyopia. What Are They?
The medical term for short-sightedness is myopia. Myopia is a very common eye condition that causes distant objects to appear blurred, while close objects appear clear.
In myopic eye, the light focuses in front of the retina instead of on the retina.
Symptoms of myopia
Symptoms of uncorrected myopia include blurred vision, headaches, eye strain and outward deviation of one side of the side end of the day. Severe/high myopia increases the risk of glaucoma, retinal detachment and early onset cataracts.
What causes myopia and can we stop it?
Read more to understand the myopia epidemic here.
The medical term for long-sightedness is hyperopia. Long-sighted people can see distant objects but have difficulty seeing up close. Long-sightedness (hyperopia) is a completely different condition from presbyopia or 老花。Presbyopia is caused by inflexibility of the crystalline lens in changing focus, whereas hyperopia is caused by shorter eyeball or the eyeball has too little refractive power.
Symptoms of Hyperopia
Not all hyperopic patients will experience visual symptoms such as red or tearing eyes, eye fatigue, squinting, headache, intermittent blurred vision, or difficulty with reading. Young patients with sufficient focusing reserve will be able to maintain clear images at both distance and near without producing symptoms mentioned above. However, older patients and patients with lower focusing reserve can be affected greatly by the symptoms if the hyperopia left uncorrected.
Presbyopia is a condition that caused by loss of elasticity of the lens in changing focus. It is an age-related process that occurs typically in middle and old age. Onset age is usually around 40 years old.